In this work, we try to cast a new light on the origins of dust crystals by accurately determining their location in the disk of HD 100546. We use Herschel observations presented by Sturm et al. 2010 of the 69 micron feature of crystalline forsterite, whose shape is temperature dependent. By comparing its shape with detailed radiative transfer models of the geometry and mineralogy of the disk, we are able to uniquely constrain the location of the forsterite crystals to a narrow region at the edge of a disk gap, where these crystals are present at very high abundance (~50%).
We suggest this unusual mineralogy may be a by-product of gap formation by a planetary companion.